Later Tim,
I was inspired by your project to read the excellent book "U-boat war patrol" and found new pictures of the MG 34 mount, this time sported by U-564,which started to convince me that what i nicknamed the "S-rune mount" could really be a standard mount for U-boat MGs. I have found it in many pictures of late type VII with Turm 0 and turm IV configuration.
(U564)
(U564)
The "S-Rune mount" in detail (below)
On Turm 0 VIIB and early C types and on type IX boats the basic Y-shaped mount can be seen more frequently, such as in the case of U-124 below:
To date none has really replied to the original question by lucasner: were the mounts attached to modified "life-belt ring holes"? so far I still havent found a clear picture showing an MG 34, its Y-mount and the conning tower area where it attaches on a turm-0 (basic) configurated boat.
I think that Lucasner assumptions are basically correct, in one of the pictures he published it's quite evident that the mount fills a life-belt hole actually, but it's possibile that mounts could be fixed to different holes on the tower designed specifically to host the MG mount, like the two that can be seen in the picture below on the portside of the turret, aft to the last life-belt ring hole (far left on the picture). Who knows?
(A propos of this picture, the UZO cover is a fake, the picture has been retouched, i managed to find the original picture which showed a normal, "naked" UZO
)
The picture below shows details of U-552 turret where the possible siting for an MG mount is visible. It's located aft of the last life belt ring hole, exactly in the same spot of the hole sited above the wood chips shown in the previous pic. A modified life-belt ring hole or something meant specifically for the gun mount?
Whatever the answer is that's the place i would probably choose to put a gun mount on a Turm 0, 1941-42 VIIC model..
Thanks for replying, I think this is an interesting subject for modellers!!
cheers
SG